Suction pumps are known for a wide variety of applications. However, they can preferably be used in breast pump devices for pumping off breast milk, or as drainage pumps for suctioning off body fluids.
There are suction pumps in closed systems which at all times move the same air within the pump chamber. However, open pump systems are also known with an air release valve which can be opened cyclically via an electromagnet.
The requirements placed on these suction pumps, in particular when they are used as breast pumps, are quite high. They should be as powerful as possible but, at the same time, relatively small. Particularly in their use as breast pumps, they should be able to operate with minimum maintenance and should be easy to clean.